Electrode for neon tubes



Nov. 1, 1932. H. HILGENBERG ELECTRODE FOR NEON TUBES Filed Aug. 20, 1928 ifelylQe-Reynventor,

Gttorneg Patented Nov. 1, 1932 UNITED STATES PATENT OFFICE l p HENRY HILGENBERG, OF CHICAGO, ILLINOIS, .#ASSIGNOR TO NEON ELECTRIC SIGN CO., INC., OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS nLnc'rBoDE Iron. NEoNTuBEs Application led August 20, 1928. Serial Ho. 300,773.

This invention relates to the electrode ends of neon or other rariied' gas filled tubes for electric signs. v

One object of my invention is to shield the outer or inactive surface of the electrode element to prevent sputtering and thus prevent the formation on the inner wall of the outer tube of gas depleting deposits, as heretofore. Y

Another object of my invention is to have the shield surround the element so that the shield and not the element will contact with the outer glass tube on failure of the element support and revent the element from uncturing the tu e and allow the escape o gas, as heretofore.

The invention consists further in the matters hereinafter described and claimed.

In the accompanying drawing- Fig. l is a face view of a portion of an electric sign equipped with neon gas lled tube sign characters, the ends of which are constructed in accordance with my invention;

Fig. 2 is an enlarged longitudinal sectional view through an electrode end of one of the sign characters on line 2 2 of Fig. l; and

Fi 3 shows an electrode end without the shiel of my invention.

lin the drawing, l, 1 indicate several neon or other raried gas lled tube characters of an electric sign, and 2 indicates the sign body on which said characters are mounted and supported'.

Each character l consists of a single length of appropriate glass tubing 3 bent. vto the shape desired and having enlarged and elongated bulb like end portions a, l to accommodate the electrodes of the character. The bulbs a, l are usually disposed at right-angles to the main body portion of the tube and extend into the sign body 2 through suitable enlarged holes or openings 2a, 2a provided therein, as shown in Fig. 2..

The electrode in each bulb portion 4l consists of an elongated metallic element 5, which may be in the form of a copper, nickel, or other metal tube, through the medium of which anA electric current is discharged into the as confined in the outer glass tube 3 to ilate the same. A lead-in e 6 is sealed in the bulb end ofthe outer glass tube 3 and' is connected with thev adjacent end of the element 5 to carry the current to and from the same in the operation of the tube. :,The inner end of the wire 6 is loo as at t, to provide a support for the element 5, which has its end at the loop crimped inward to fit about the loop and be held v therebyy out of contactwith the glass seal for the wireso as not to crack the seal as the element comes to a high heat in the operation of the tube. The element 5 has anout side diameter considerably less than the inner diameter of' the bulb end of the tube 3 and 1s supported axially therein and out of contact with said tube by the loop end of the wire 6. y

The structure so far described is in general use but is faulty for two reasons. First sputtering is not prevented because the outer or inactive side of the element 5 is exposed. rlhe emission of sputtered material from the surfaces of the element 5 is in straight lines, and that emitted from the outer or inactive Surface of the element travel straight across to the opposite wall of the outer tube 3 and develop heat on striking the tube wall. Such particles on striking the inner wall of the tube 3 form lthereon a deposit as at a in Fig. 3. lin building up this deposit, portions of the active gas from Within the tube are entrapped, thereby lessening the eciency of the tube and reducing its life by depleting its gas content. L

'lhe second objection to the structure so far described, is that the exposed element 5 when highly heated and falling against the glass wall of the outer tube 3 on failure of the wire support 6 will puncture the tube 3 and allow the gas confined therein to escape.

lin accordance with my invention, l shield the element 5 on its outer or inactive side, and thus prevent the sputtered material emitted from that side reaching the Wall of the outer tube and from building up a deposit on the tube wall to deplete the quantity of gas in the tube, as heretofore. The shield further prevents the heated element 5 from contacting with the tube wall on failure of the wire suport, thereby preventing the heated element from uncturing the tube wall', as before.

In gig.- 2, the shield is shown and is indicated by the reference numeral 7. The shield ma be in the form of a glass tube substantia ly as long as the element 5 and fitting over the same with a sliding fit so that the shield maybe readily and easily slid on and off the element 5 when fitting and assembling the arts. P The opposite ends of the shield 7 are directed inward, as at 8 and 9, so that the shield is prevented from sliding od the element 5 when handling the same as Well as when handling the completed tubes and the signs equipped therewit The shield 7 has an outside dlameter less than the inside diameter of the bulb end of the tube 3 and is supported by the element 5 out of contact with said tube. The shield '7 does not contact with the seal in the outer tube 3 where the wire 6 extends through so that the shield when heated by the .clearly il ustrated in full lines in Fig. 2. On

the other hand, the shield 7 also prevents the heated element 5 from contacting with the glass -wall of the outer tube 3 on failure of the wire support 6, as indicated in dotted lines in Fig. 2.

With my invention the life and eiiiciency of the tube 3 is practically assured, because the gas depleting deposits can not form, and the chance of puncture of the outer tube on failure of the electrode support is completely eliminated.

The details of structure shown and described may be variously changed and modified without departing from the spirit and scope of my invention.

I claim as my invention:

1. The electrode end of a neon or other rarified gas filled tube, consisting of the outer tube, an electrode element supported therein, and means providing a shield about the element to prevent the sputtered material emitted from the outer or inactive surface thereof from reaching the opposed wall of the outer tube, said shield bemg carried by said element.

2. The electrode end' of a neon or other rariied gas filled tube, consisting of the outer tube, an elongated tubular metallic electrode element supported therein, and a shield fitting about and supported by said element to prevent sputtering thereof, said shield being substantially as long as the element so as to cover the same.

3. The electrode end of a -neon or other rarified gas filled tube, consisting of the outer tube, an elongated metallic electrode element supported in said tube, a tubular shield litting about and supported by saidelement to prevent sputtering thereof, said shield being substantially as long as the element to cover the same, and means preventing displacement of the shield on the element.

4:. The electrode end of a neon or other rarifed gas filled tube, consisting of the outer tube, an electrode element supported therein, and a glass shield supported by said element and covering the outer or inactive surface thereof.

5. The electrode end of a neon or other rarified as filled tube, consisting of the outer glass tu e, an electrode element, means for supporting the element in the outer tube, and means interposed between the element and the outer tube to prevent the element from contacting with the outer tube on'failure of the support for the element, said means being carried by the element and normally out of contact with the outer tube.

6. The electrode end of a neon or other rarified as filled tube, consisting of the outer glass tu e, an elongated metallic electrode element, means supporting the element from one end within said outer tube, and 'a tubular glass shield supported by said element and tting about the same to prevent the element from contacting with the outer tube on failure of the support for the element, the shield having open ends and fitting closely about said element and held from endwise displacement thereon.

7. The electrode end' of a neon or other raried gas lled tube, consisting of the outer tube, an elongated metallic electrode element within said outer tube, a lead-in wire sealed in the outer tube and connected with the electrode element at one end to support the element axially in the outer tube, and atubular glass shield fitting about the element and supported thereby to prevent contact of the element with the outer tube on failure of the support for the element.

In testimony whereof I aix my signature.

HENRY HILGENBERG. 

